Category A Healthy. House

Net Current in Utilities

After purchasing a gaussmeter, an electrician was surprised to discover an elevated magnetic field throughout his entire driveway and a portion of his home. Upon learning that the field did not de­cline when he shut off the power to his home at the main breaker, he concluded that the source of the field was from net current in the gas line. A gas company technician visited the siteand confirmed that the gas line was carrying electricity. There was no cause for concern, he said, because the amount of electricity was small.

The electrician was not comforted by such reassurances. As a specialist in complex wiring

techniques for boats and marinas, he was familiar with the problems of electrolysis and galvanic ac­tion resulting from electricity straying from its in­tended path. He had even witnessed boats at the local marina whose metal had gradually dissolved from exposure to net current. Thus, the electrician reasoned, the net current in his plumbing and gas lines would cause the lines to deteriorate at an ac­celerated rate. After informing the gas company that the galvanic action in the pipes was a liability for the company because of the possibility of an explosion, the electrician was finally able to per­suade the them to take his complaint seriously.

Measuring Magnetic Fields

Magnetic fields are measured with a gaussme­ter. A homeowner might consider purchasing a gaussmeter for one or more of the following reasons:

• to determine safe distances from various household appliances

• to help detect wiring errors that not only produce magnetic fields but also may be fire and electrocution hazards

• as a periodic safety check to determine that no new problems have developed in household appliances

• as a periodic safety check to ensure that no new magnetic fields are entering the home through utility lines

There are two basic types of gaussmeters: single and triple axis. Single-axis meters tend to be less expensive and are slightly more dif­ficult for a novice to use because they must be rotated to align with the flow of the magnetic field in order to detect it. Orienting a triple­axis meter with a field is not necessary because this meter requires positioning only within the range of the field. Less expensive gaussmeters will give false readings when measuring cer­tain magnetic fields such as those generated by computers and electrically ballasted fluo­rescent lights. The following gaussmeters are widely available and are generally adequate for measuring household fields:

• MSI EMF Meter is a single-axis meter that is accurate for field frequencies between 60 and 180 hertz but does not measure higher frequency fields.

• Tri-Field Meter is a low-cost triple-axis meter for measuring magnetic and other fields. The meter may overestimate 60- hertz fields because of interference when higher frequency fields can also be de­tected.

Electromagnetic Fields: Challenging Unsafe Limits


Take on the military, government, electric utili­ties, appliance and cell-phone manufacturers, and the owners of television, radio, and other high fre­quency antennas and you’re in for a major fight. The stakes are huge because since 2003 insurance companies no longer cover eventual (because still unproven) damages caused by electromagnetic fields (EMFs). These are emitted by all from the smallest electrical devices and grounding circuits to high-tension power lines and radar systems.

"Scientists who have persisted in publicly rais­ing the issue of harmful effects of any portion of the electromagnetic spectrum were discredited, and their research grants were taken away," says orthopedic surgeon Robert O. Becker.9 In 2000, the double Nobel prize candidate stated,"I have no doubt in my mind that, at the present time, the greatest polluting element in the Earth’s en­vironment is the proliferation of electromagnetic fields."b

Power utilities and the communications indus­try are especially powerful, says David Carpenter, director of the Institute for Health and the Envi­ronment at the State University of New York (Al­bany). "They have infiltrated the world of science and become the dominant spokespersons to gov­ernment and the public on this issue," he said in a telephone interview. "There’s a huge amount of conflict of interest involved."c

Up to now, industry’s public relations spin doc­tors have delivered. Most lay people, scientists, and journalists still scoff at the idea that EMFs could be dangerous. Butthetide isturning. ln recentyears it seems not a month or season has gone by without another alarming study being published. PR spin is spinning out of control.

Since 1979, more than a dozen epidemiologi­cal studies have associated child leukemia with overexposure to residential magnetic fields. They found that the risk of leukemia doubled when the 24-hour average dose of EMFs measured as low as 1.4 milligauss in young boys. Some studies even found the risk quadrupled above 3 or 4 mil­ligauss. Based on these studies, in 2001 the Inter­national Agency for Research on Cancer (IARC) classified residential — 60 hertz or Extremely Low Frequency (ELF) — magnetic fields as "possibly carcinogenic."d In Quebec, where 73 percent of homes are heated with cheap electricity, one out of five children receives a daily average dose of at least 2 milligauss, according to McGill Univer­sity professor and Hydro-Quebec researcher Jan Erik Deadman. Quebec also has the highest rate of child cancer in Canada (16.5 cases per 100,000 children), according to statistics obtained from the Public Health Agency of Canada. Besides ionizing radiation (X-rays), there are few proven causes of child cancer but many are suspected, including exposure to EMFs, says IARC, which is part of the World Health Organization (WHO).

Pressed by industry lobbyists, WHO has flip – flopped on whether to recommend countries take action to reduce public exposure. In the ab­sence of direct proof of a biological mechanism by which EMFs damage genes, WHO still stands by the 1,000 milligauss daily public exposure limit recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).e But this limit only aims to avoid immediate effects of acute exposure, such as inducing current in the human body. It does not address cancer or other risks from long-term exposure.

Since magnetic fields are generated by the flow of electric current and since global power de­mand is always on the rise, public exposure has multiplied. Electric fields are generated when an appliance is plugged to receive voltage but not necessarily turned on to allow current flow. Few health studies have focused on electric fields. However, in 2007 British scientists discovered that electrically charged particles increase the risk of asthma because they stick to lung and respiratory tract tissue/

In May 2007, the medical journal The Lancet criticized WHO for ignoring important evidence while developing international health guidelines.9 WHO’s EMF research project was also discredited for being 50 percent financed by industry. "Just months after leaving his post as the head of WHO’s EMF project, Mike Repacholi is now in business as an industry consultant," reported Microwave News. b Repacholi denies ever putting industry’s interests above the public’s.

WHO responded by acknowledging that fur­ther EMF research is needed, that "the use of pre­cautionary approaches is warranted" and that "exposure limits should be based on a thorough examination of all the relevant scientific evi­dence." However, it also stated that"assumingthat the association is causal, the number of cases of childhood leukaemia worldwide that might be attributable to [EMF] exposure…represents 0.2 to 4.9 percent of the total annual incidence of leukaemia cases, estimated to be 49,000 world­wide in 2000. Thus, in a global context, the im­pact on public health, if any, would be limited and uncertain."’

This assertion is challenged by experts such as

Carpenter. From 1980 to 1987, he coordinated EMF studies as head of the New York State Power Lines Project. "WHO is grossly underestimating the im­pact," he said in a telephone interview."lt is ignor­ing exposures from appliances, radio frequencies (from wireless appliances and antennas, etc.), as well as other exposures outside of homes, for ex­ample in school. In the mid-1980s, the Savitz study concluded 10-15 percent of all child cancers re­sulted from magnetic field exposure from pow­erlines. Nobody pointed out any errors in Savitz’s logic. It is not unreasonable to say the total contri­bution of EMFs is 20 to 35 percent of child cancers. In my mind, the evidence is overwhelming."

Hundreds of medical studies have also linked various sources of EMFs to numerous ailments and diseases, ranging from depression to skin, eye, heart, reproductive, and neurological prob­lems. That’s why a number of public health experts have mandated or recommended stricter expo­sure guidelines and regulations to protect public health:

• Physicians Suzanne and Pierre Deoux/ French experts in healthy housing, recommend kee­ping these distances from transmission lines: 250 meters from 400 kilovolt lines, 150 meters from 225 kilovolt lines, 100 meters from 63 to 90 kilovolt lines, 40 meters from 20 kilovolt lines, and 5 to 10 meters from transformers. These are conservative by North American standards since magnetic fields are weaker in Europe, where 220-volt tension is used. (Electric fields are thus higher and more worrisome there.)

* In January 2007, the Connecticut Department of Public Health recommended imposing a 10 milligauss limit at the edge of rights-of-way

(land reserved for passing powerlines). Con­necticut Light and Power’s consultants (in­cluding Mike Repacholi) claimioo milligauss is a safe limit.

• In 1996, Sweden recommended that new homes and schools be built at least 75 meters from powerlines and electrical equipment to avoid exposures above 2 milligauss.1

• Since 2000 in Switzerland, new electrical lines and equipment must emit below 10 milligauss in areas where people spend several hours a day. m

• Ontario and Wisconsin politicians have pro­posed legislation requiring that utilities stop using the ground as a return path for over 70 percent of electrical current. Ground currents often harm farm animals as well as humans worldwide."

• Since 1999, several jurisdictions limit the power densities emitted by new or modified base cel­lular telephone antennas. In Switzerland and Toronto, for example, they must be 90 percent lower than the international standard of 1,000 microwatts per square centimeter.0

• In 2007, Carpenter led a group of experts who reviewed 2,000 scientific studies before decla­ring that current EMF public safety limits are inadequate to protect public healths They rec­ommended: a 1 milligauss limit for housing ad­jacent to all new or upgraded power lines and a 2 milligauss limit for all other new construc­tion^ 1 milligauss limit for existing housing to protect children and pregnant women; and a limit of 0.1 microwatt per square centimeter

(also 0.614 volts per meter) for outdoor cumu­lative exposure to radio frequencies.

While outdoor sources are not always the domi­nant source of electropollution, many countries and public utility commissions in California, Colo­rado, Connecticut, and Hawaii have adopted "pru­dent avoidance"q policies. These strike a balance between protecting public health from potential effects of EMFs and implementing reasonable – or modest-cost mitigation measures to lower public exposure. Such efforts send clear signals to buil­ding owners: they too should apply simple and affordable mitigation measures because in most cases the dominant sources of EMFs originate in­doors.

a. Robert 0. Becker. Cross Currents. Tarcher, 1990, page 300.

b. Linda Moulton Howe. British Cell Phone Safety Alert and an Interview with RobertO. Becker, M. D [online]. [Cited November 23,2007.] Council on Wireless Technology Impacts, 2000. energy fields. org/science/becker. html

c. See Albany. edu. ihe.

d. International Agency for Research on Cancer. IARC Finds Limited Evidence that Residential Magnetic Fields Increase Risk of Childhood Leu­kaemia [online]. [Cited November 23, 2007.] Press Release N0.136, June27,2001. iarc. fr/ENG /Press_Releases/archives/pri36a. html

e. International Commission on Non-Ionizing Ra­diation Protection. Guidelines for Limiting Ex­posure to Time-Varying Electric, Magnetic, and

Electromagnetic Fields (Up to 300 GHz) [online]. [Cited December 10, 2007.] icnirp. org/docu ments/emfgdi. pdf

f. K. S Jamieson et al.’The Effects of Electric Fields on Charged Molecules and Particles in Individ­ual Microenvironments." Atmospheric Environ – ment. Vol. 41, no. 25 (April 2007), pp. 5224-5235.

g. Maria Cheng. "WHO Criticized for Neglecting Evidence" [online]. [Cited November 27, 2007.] ABC News, May 7, 2007. abcnews. go. com/ Health/wireStory? id=3i4974o See also An­drew D. Oxman et al."Use of Evidence in WHO Recommendations" [online]. [Cited December

10.2007. ] The Lancet. Vol. 369, no. 9576 (June 2, 2007), pp. 1883-1889. thelancet. com/journals/ lancet/article/PllSoi4o6736o76o6758/abstract

h. "It’s Official: Mike Repacholi is an Industry Con­sultant." Microwave News. Vol. 26, no. 8 (Novem­ber^, 2006), pp. 1-3.

i. World Health Organization. Extremely Low Fre­quency Fields [online]. [Cited December 10, 2007.] Environmental Health Criteria Mono­graph No. 238, 2007. who. int/peh-emf/publica tions/elf_ehc/en/index. html

j. See medieco. info.

k. "Public Health Officials Urge Precaution to Limit Cancer Risk" [online]. [Cited December

10.2007. ] Microwave News. Vol. 27, no. 1, pp. 1-3. microwavenews. com/docs/mwn.1-07.pdf

l. J. M. Danze et al. L’habitat sain? L’electrosmog: le maitriser; le connaitre et s’en proteger. Editions Marco Pietteur, 2002.

m. Swiss Agency for the Environment, Forests and La n d sea pe. Electrosmog in the Environment [on­line]. [Cited December 10,2007.] Swiss Federal Office for the Environment, 2005. bafu. admin. ch/php/modules/shop/files/pdf/phptbAigJ. pdf

n. Electrical Pollution Solutions [online], [Cited No­vember 27,2007.] electricalpollution. com

o. City of Toronto. Reports and Publications: Radiation [online]. [Cited December 10, 2007.] toronto. ca/health/hphe/radiation/radiofre quency. htm

p. David Carpenter and Cindy Sage, eds. Biolnitia – tive Report: A Rationale for a Biologically-Based Public Exposure Standard for Electromagnetic Fields (ELF and RF) [online]. [Cited December 10, 2007.] Bioinitiative Working Group, August 31, 2007. bioinitiative. org/report/docs/report. pdf

q. Leeka I. Kheifets. The Precautionary Principle and EMF [online]. [Cited December 10, 2007.] who. int/pehemf/meetings/southkorea/en/ Leeka_Kheifets_principIe_.pdf

Other excellent sources of information on EMFs are: powerwatch. org. uk/docs/emhealth. asp; next – up. org;and buildingbiology. net (to find an EMF in­spector in the US and Canada).

Andre Fauteux, a journalist by training, has spe­cialized in healthy housing since 1990. A former Montreal Gazette reporter, in 1994 he launched the newsletter La Maison du ne siecle (21st-Century Housing), which in 1997 became Canada’s first green-home magazine. See 21esiecle. qc. ca.

Magnetic Fields

The importance of checking the electrical instal­lation under load with a gaussmeter before oc­cupancy is demonstrated in this case study. An electromagneticallysensitiveclient consulted with John by telephone throughout the construction of her home, which was built according to specifi­cations similar to those outlined in this book. After the client moved into her new home, she began experiencing symptoms that occur when she is exposed to elevated magnetic fields, such as ring­ing in the ears and inability to concentrate. Using a gaussmeter, she discovered that about half of the home registered over 5 milligauss. She called John in a state of panic, convinced that her house was ruined and that she would never be able to live in it.

John contacted the client’s electrician and of­fered to help him diagnose the problem over the

telephone. Under John’s guidance, the electrician conducted field testing with the client’s gauss­meter. From the measurements, it became clear to John that the problem was located in the sub­panel controlling a section of the house. At that point, the electrician immediately realized what he had forgotten to do. Some panels and subpan­els are interchangeable except for a single screw that must be removed from the neutral bus bar to electrically isolate it from the ground wires in the panel. Called a bonding screw, it was causing net current in all circuits in the subpanel. The electri­cian simply removed the bonding screw and the magnetic fields dropped in an instant to less than 0.2 milligauss.

detected throughout the structure before it is energized, there is reasonable cause to suspect that fields are entering from an outside source. At this point, consult an expert who can prop­erly block them. Because neighborhood con­ditions may change over time, fields should be checked regularly.

Along with proper bonding and ground­ing, grouping the entry points of all utili­ties will also provide more protection against lightning damage. However, this is not a sub­stitute for lightning rods and lightning surge protection, which are designed to protect the home during a lightning storm.

The following are specifications for pre­venting the entry of magnetic fields through utility services:

• All utilities, including telephone, cable TV, gas, and water, shall enter the build­ing at approximately the same location, within a four-foot radius.

• All utilities entering the structure shall be properly bonded immediately prior to en­try in accordance with the National Elec­trical Code (NEC).

• Bonds or grounds shall occur at only one point along each utility in accordance with the NEC.

• All utilities shall be tested with a gaussme­ter when the house power is turned off. If magnetic fields are detected, inform the owner or architect immediately.

Magnetic Fields from Panels and Subpanels

Many electrical panels and subpanels emit substantially elevated magnetic fields. This problem arises because breaker and neutral bus bars are configured so that the neutral and hot wires are separated once fastened in place, causing magnetic fields as discussed earlier. Some electrical panels are configured with the neutral bus bar split to run alongside the breakers. To cancel the fields, the hot and neutral wires would be the same length and installed beside one another. We recommend that such reduced field configuration panels and wiring be specified as indicated below:

• Panels and subpanels shall be configured so that hot and neutral field cancellation is possible.

• The following panels and subpanels are acceptable: Siemens EQIII, standard load center electrical panels, and subpanels with split neutral.

• Hot and neutral wires from the same run are to be installed adjacent to one another.

• Hot and neutral wire lengths shall be equal.

Dielectric Unions

A dielectric union is a plastic joint that acts as an insulator, preventing the passage of elec­tricity between conductive materials. In a typical home, conductive gas and water lines come into contact with appliances in several places. For example, water lines feed into re­frigerators with icemakers, and gas lines feed into motorized furnaces. Should a fault occur in the appliance, wayward electricity will be distributed through the piping unless a dielec­tric union is used to isolate the appliance from the utility pipes. “Electrified” piping is unde­sirable for the reasons listed below:

• Magnetic fields will radiate out from the pipes.

• Net current in gas lines is an explosion hazard.

• Pipes carrying net current can become an electrocution hazard.

• Electric current flowing through pipes causes electrolysis, which results in de­composition of the pipes.


Bonding and Grounding

As discussed in Division 2, it is important to choose a site that is free from elevated mag­netic fields generated from overhead power lines. Magnetic fields caused by faulty wiring in a neighbor s home also can be transferred into your home through utility service lines. Be­cause electricity will follow all available paths, metal plumbing, gas lines, cable TV lines, and
tion of a 14-cent electrical nut to separate the two neutral wires. The magnetic fields throughout the house dropped to 0.5 milligauss, considered to be an acceptable level.


This case study illustrates a simple code violation that went unnoticed by the electrical inspector. If the inspector had used a gaussmeter, the error would have been easily detected before final closeout. Surprisingly, such testing is not com­mon practice. Had the tenant not used a gauss – meter, the code violation might never have been revealed.

telephone lines can become pathways for un­invited net current. Consequently, taking sim­ple precautions to prevent such an occurrence is prudent when site conditions allow. Al­though the National Electrical Code mandates grounding and bonding, it does not dictate the configuration of utilities entering residen­tial structures. By grouping the entry points of all utilities and providing proper bonding, any net current traveling through public utility lines will be shunted back without ever enter­ing the home. However, pathways of elevated magnetic fields may be created in your yard. These too can be blocked, but will require the expertise of a knowledgeable consultant.

If site conditions do not allow for the grouping of all utilities, then testing with a gaussmeter for unwanted fields with the house power turned off would be a prudent safety precaution, both during construction and pe­riodically thereafter. If new magnetic fields are

Magnetic Fields from Three – and Four-Way Switches

Lights switched from two different locations are called three-way switches. When lights are switched from three or more locations, they

Magnetic Fields from Three - and Four-Way Switches


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Magnetic Fields from Three - and Four-Way Switches

A: 1/2 switched outlet. Both hot and neutral pre-scored conduction tabs must be snapped off when the upper and lower outlets are supplied by separate breakers.

B: Ganging Neutrals. This wiring configuration is wrong and will create net current and magnetic fields.

C:This diagram shows the correct configuration, which will not generate magnetic fields.

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are called four-way switches. A correctly wired three – or four-way switch will not emit mag­netic fields. However, these switches are often wired incorrectly and thus become a source of magnetic fields that can radiate throughout the room. To avoid improperly wired three – or four-way switches, specify the following:

• Three-wire Romex shall be used between the switches when wiring a three-way switch (see illustration). If alternate wire is used, it shall be twisted.

• Each three – or four-way switch must be controlled by a single breaker.

• All wiring for three – or four-way switches shall be contained in a single run of wire or a single metal conduit. All runs not in a conduit must be bundled.

Fields from Dimmer Switches

Dimmer switches are a source of magnetic and radio frequency fields. If these switches are used, they should be located at a distance from seating and sleeping areas. The most ex­pensive name-brand dimmers tend to emit smaller fields. Choose a model that emits no fields when all the way on or all the way off.


Electromagnetic Fields

Electric and magnetic fields are commonly discussed as if they were a single entity termed electromagnetic fields or EMFs. In fact, the two phenomena, although interrelated, are distinctly different and they will be discussed separately in this chapter. Chart 16.1 presents a comparison of the two.

Magnetic Fields

Basic Home Wiring and Net Current

Although the relationship between human health and elevated fields remains contro­versial, there are definite safety concerns as­sociated with wiring techniques that cause magnetic fields. In recognition of such haz­ards, the National Electrical Code has man­dated safer wiring. Your electrician may be puzzled if you declare that you want a home free of all elevated magnetic fields, but if you say you want a home free of net current in compliance with the electrical code, you are
saying the same thing in a language electri­cians understand.

Most household wiring consists of no-volt lines. If you were to peel back the outer insu­lating plastic on a piece of Romex, the most common wiring used, three strands would be revealed — one black, one white, and a third either green or bare copper. The black strand is referred to as the hot wire because it draws electricity from the breaker box or panel and delivers it to light fixtures and appliances. The white wire, called the neutral, returns the elec­tricity to the panel after it is used. The green or bare copper wire is the ground wire. Under normal conditions, it does not carry electric­ity. However, if a malfunction such as a short occurs, it serves as a fail-safe protective de­vice, carrying power back to the ground un­til the breaker is tripped and the power to the faulty circuit is cut off, thereby helping to pre­vent shock and electrocution.

When the electrical system is functioning as it should, the amount of electricity flowing

out to an appliance through the hot wire is equal to the amount of electricity flowing back through the neutral wire. This equal and op­posite flow of current through the wires cre­ates a net current that cancels to zero, which is the desired condition. When, for various rea­sons, unequal supply and return currents are unable to cancel each other out, a net current is present and a magnetic field is created.

A second condition that creates net cur­rent with associated magnetic fields occurs when the neutral and hot wires are separated by distance. When Romex wiring is used, the hot and neutral wires run adjacent to one an­other inside the plastic insulating sheathing, allowing them to cancel each other out. In an older wiring system known as knob and tube,

the hot and neutral wires were run on sepa­rate studs. The distance between the wires re­sulted in an uncancelled magnetic field. There was also no grounding. Although now prohib­ited by code, this dangerous system of wiring, along with its associated elevated magnetic fields, is still found in many older homes.

The National Electrical Code prohibits the production of net current. This requirement should protect people from elevated mag­netic fields as well. Unfortunately, subtle code violations resulting in the production of net current frequently occur, not only causing el­evated magnetic fields but also increasing the risk of fire and electrocution.

We have identified several commonly used wiring techniques that create very high

Chart 16.1: Comparison of Electric and Magnetic Fields

Electric fields

Magnetic fields

Flow in straight lines in all directions from the source unless conductors attract them

Radiate out from the source, flowing in loops

Can be easily shielded

Difficult and expensive to shield {even lead is not effective)

Attracted by conductors such as metal, saltwater bodies, and people

Penetrate all normal building materials

Present when switches for machinery are off or on

Occur only when appliances are switched on and current is flowing

Not widely recognized presently in conventional circles as a health threat

Safe-exposure limits not regulated by the US gov­ernment, though Sweden has set limits

Reportedly affect the nervous system and can cause insomnia, anxiety, depression, aggressive behavior, and a higher risk of leukemia1

Reportedly affect cellular function and have been statistically linked in some studies with increased cancer cell growth rate, Alzheimer’s, miscarriage, and birth defects, while some sensitive individuals report physical reactions

Electrical code permits but does not mandate wiring for reduced electric fields

Electrical code offers protection against exposure to magnetic fields produced by wiring in the structure, with some exceptions

Proper use of electric field meters requires expertise

Easily measured with a gaussmeter

magnetic fields. Although these techniques are considered to be code violations by most code interpreters because they create net current, they often go unnoticed by building inspec­tors. Case studies 16.1 and 16.2 are accounts of such occurrences. Following are specifications for wiring techniques and inspections for pre­venting and detecting elevated magnetic fields in wiring:

• All wiring shall be performed in strict accordance with the National Electrical Code.

• The ganging of neutral wires from differ­ent branch circuits is prohibited.

• Hot and neutral wires must be bundled together, as in Romex. Separate wires fol­lowing separate paths are prohibited.

• Bonding screws shall be removed from the neutral bus of all subpanels per manu­facturer s instructions.

• When wiring a half-switch outlet using two separate breakers for each half of the outlet, the two neutral wires must not make electrical contact. This is accom­plished by breaking off the prescored con­ductive tabs between the two sections of the outlet per manufacturer s instructions.

• Neutral wires on half-switched outlets shall not be mixed. They shall remain paired with corresponding hot wires.

• When wiring enters an electrical box from more than one circuit, care must be taken to ensure that the wires from the differ­ent circuits are isolated from one another so that electricity return paths are not shared. This can be done by installing wir­ing so that all wiring entering an electrical box is from the same circuit.

• At the time of the final electrical instal­

lation, and in the presence of the general contractor, architect, or owner, the electri­cian shall apply a minimum load of three amps to the distal end of each electrical circuit. The home shall be inspected un­der load using a gaussmeter. Any elevated ambient magnetic fields greater than 0.5 milligauss will indicate the presence of net current. These measurements should be taken about a foot away from switches or outlets as the levels right at the switch or outlet will generally be greater than 0.5.

* It is the responsibility of the electrical contractor to locate and eliminate net cur­rent caused by the electrical installation.

• The home shall be reinspected for any net current resulting from the work of other trades in the completed building.

An inspection should be performed after elec­trical installation but before wall surfacing is installed so that any net current resulting from errors in the electrical installation can be determined and easily remedied. The elec­trician should be responsible for correcting these errors. Reinspecting after the surfacing materials are installed will help determine if other trades have caused damage to the elec­trical system. For example, a nail might pene­trate the wiring and cause electrical problems. This damage would not be the fault of the elec­trician, but the electrician would need to cor­rect it.

Air Filtration

The addition of filters to ventilation and forced-air heating and cooling systems allows for greater control of air quality. As discussed above, indoor air is often too polluted to prop­erly nourish occupants. The first line of defense against such pollutants is to provide an ample supply of fresh outdoor air through ventila­tion. Unfortunately, “fresh” air, although con­siderably cleaner in most cases than indoor air, often contains allergens in the form of molds, pollens, and manufactured pollutants,



How it works






To bring fresh air into the home and exhaust stale air

Takes advantage of natural air pat­terns. Strategically placed openings encourage fresh air to move diagonally through the space, entering low and exiting high.

• Quiet

• Free

• Maintenance-free

• Does not require energy to operate

• Can be drafty and create greater heating/cooling load

• Air cannot be filtered

• Allows for only minimal control

• Requires high level of occupant participation

• Suitable as sole means of ventila­tion throughout the year only in very temperate climates

• Outdoor air must be clean

This strategy works best in mild climates and can be enhanced through various roof-ventilation techniques.

Exhaust fans

To remove local­ized pollution at the point of generation, primar­ily in kitchens and baths

Stale and moisture­laden air is sucked out of the house at the point of generation, using a powerful fan.

• Pollution is quickly removed before the rest of the home is affected

• Can depressurize home, causing infiltration and possible back – drafting

It is important to supply replace­ment air when fans are in operation. Exhaust fans are required by code in bathrooms and laundry rooms without operable windows.

Supply fans

To provide fresh air

A fan blows fresh outside air into the home, creating positive pressuriza­tion that forces stale air out.

• Inexpensive

• Pressurization of home prevents contaminants from infiltrating from outdoors

• Cold drafts around fan in winter

• Pressurization can cause hidden moisture prob­lems as humid air is forced through wall openings and then con­denses

Adequate and strategically placed vents are required to exhaust air.

This is a good strat­egy for venting a basement.

Supply fans are not suitable for dispel­ling kitchen – and bath-generated pollution.



How it works







To provide fresh air and exhaust stale air while control­ling pressurization

A set of fans brings in fresh air through intake and distributes it, then exhausts stale air to the exterior.

• Provides balanced pres­surization

• Comes equipped with, or can be adapted for, various filtration strategies

• Does not moder­ate temperature or humidity of incoming air

• Can be noisy

• Relatively small fans are standard and are insuf­ficient to handle large amounts of gas filtration

Air-to-air heat exchange or HRV (heat recovery ventilator)

To supply fresh outdoor air into the home while exhausting stale air and maintaining indoor tempera­tures

Incoming fresh air passes through a series of chambers adjacent to outgo­ing exhaust air. Heat, but not air, is transferred.

• Reduces heating and cooling costs by recovering 60 to 80% of heat

• Chambers can be made of paper, which collects dirt, or plastic, which can outgas; choose one with metal chambers

• More costly initially than other balanced ventilators

• Causes conden­sation; must be maintained to remain mold-free

Most effective for tight homes in cold climates. Energy re­covery ventilators (ERVs) also recover humidity VenMar Ventila­tion, Inc.

Fresh-air intake incorporated into forced-air system

To provide fresh air when the central forced-air system is operating

A 3" to 6" metal pipe with damper valve provides fresh air into the furnace supply stream.

• Inexpensive to retrofit

•Ventilation supply air is preheated or precooled

• Makes use of existing ductwork for distribution

• Creates slight positive pressur­ization and can compensate for air lost through leaky ducts

• Operates only during heating or cooling season

• Depends on a well-maintained heating and cooling system to deliver good – quality air

Screen all intake pipes to prevent rodent infestation.

including exhaust fumes, smoke, and pesti­cides. When your immediate surroundings are less than perfect, you may wish to incorpo­rate some form of filtration into your home.

Home ventilation systems can easily be adapted to filter large particles like pollen and mold spores. However, most home ventilation systems are not equipped with very powerful fans and therefore cannot handle the air re­sistance created by some of the more efficient filtration methods, especially those designed to remove gases. Consequently, whole-house filtration is often more successfully combined with the forced-air distribution system. Stan­dard filters used with most forced-air systems are designed primarily to prevent large parti­cles from harming the motor, and are insuf­ficient to effectively filter out small particles injurious to human health. Most forced-air equipment must be adapted to receive ad­ditional filtration systems. When equipped with good filters, a forced-air system will not only clean fresh intake air but also continue to clean air as it recirculates.

Filter efficiency rating systems such as the “dust spot” and “arrestance” systems have been developed by filter manufacturers to provide information about the ability of a filter to re­move large particles from the airstream. This information is of limited use when evaluating filter effectiveness for removing small parti­cles of less than 5 microns, which can be the most damaging to health. In 1999, the Ameri­can Society of Heating, Refrigeration and Air Conditioning Engineers published a new fil­ter rating system that goes by the acronym MERV. This stands for Minimum Efficiency Reporting Value and is a much better way of rating the ability of filters to remove small particles. The system currently rates filters on a scale of 1 to 16, with the higher number ratings representing filters that can remove smaller particles. Although they are currently not rated by the MERV system, a HEPA filter would likely rate a 17 or higher.

Adequate MERV filters are currently avail­able that will fit into a standard furnace filter slot. For example, a MERV 8 filter is rated to remove greater than 70 percent of particles in the 3- to 10-micron range. This will remove most, but not all, mold spores and dust and should be considered as a much better alter­native to the standard fibrous furnace filter. The Filtrete Ultra Allergen Reduction Filter #1250 is a MERV 11 filter (removes 65 to 80 percent of 1- to 3-micron particles) manufac­tured by 3M. It is commonly available at Lowes and Home Depot and will also fit in standard і-inch furnace-filter slots.

While higher MERV-rated filters as well as HEPA systems are available, these more effi­cient filters tend to create more resistance, re­quiring a much larger filter to allow air to flow through them. They do not fit into or work well with standard HVAC systems. Note that when changing from a standard furnace filter to a more efficient filter it is important to replace it after one months use before going to the reg­ular three-month maintenance schedule rec­ommended by the manufacturers because the filter will be overworked when first installed in a dirty environment. If the new type of fil­ter continues to clog too quickly, there maybe a larger than normal dust load in the building. John has observed this when an air path to the attic or crawlspace exists that pulls dirt or in­sulation fibers into the system.

Most mechanical filters that remove par­ticles by filtration actually become more effi­cient as air flows through them. They remove particles as a sieve does. As the filter loads, the airflow slows and smaller particles can then be removed. The filter must be replaced be­fore airflow is impeded. Electrostatic filters don’t do as good a job of removing particles when they get dirty and must be cleaned often to achieve the manufacturer’s stated MERV ratings.

Further Reading

Bower, John. Understanding Ventilation: How to De­sign, Select and Install Residential Ventilation Sys­tems. The Healthy House Institute, 1995.

Mazria, Edward. The Passive Solar Energy Book. Rodale Press, 1979.

Chart 15.3: MERV Ratings Compared to Other Filter Ratings


Particle size range


Particle size range, pm


3 to 10 pm

1 to 3 pm

.3 to 1 pm


Dust spot






• Typical residential filters

• Pollen, dust mites


















■ 1" residential pleated filter • Pollen, dust, dust mites, most molds, most spores



















• Moderate efficiency residen­tial pleated filter (some may need furnace modification for installation)

• All of above and Legionella























• Specialty filter (usually need furnace modification for installation)

• All of above and smoke, bacteria



















Filter type


How it works





Standard furnace filter, MERV


Filters out large particulate mat­ter to safeguard the motor, not the inhabitants

A coarse,

1 "-thick filter traps large particles.

Removes less than 20% of particulate matter; does not significantly remove small particles

* Inexpensive

• Easy to change

* Indoor air quality not significantly improved

* Does not remove signifi­cant levels of mold spores

Can easily be replaced with 1" pleated panel filter, which will raise efficiency to MERV 6-11

Medium efficiency extended surface (pleated panel) filter, MERV 6-11

Particulate filter

Air is strained through a pleat­ed (extended surface area) filter that main­tains airflow.

Removes 20­70% of particu­late matter

• Relatively inexpensive

• Sufficient for most general filtration

• Airflow resis­tance can be low enough to use with most HVAC ventila­tion systems

• Removes many mold spores

• Filtration is inadequate for very polluted environments and/or very sensitive people

• Does not filter out gaseous pollution

Many are now available that will work with standard HVAC systems.

Media filters become more efficient with time as pores become smaller, but air resistance increases.

HERA (high efficiency particulate air) filter

Particulate filter

Polyester or fiberglass fibers are bound with synthetic resins, creating a medium with extremely small pores.

Removes over 99.97% of par­ticulate matter at 0.3 microns

• Can remove minute particles for extremely clean air – Can remove cigarette smoke and almost all mold spores

• High airflow resistance requires pow­erful fan

• Expensive

• May require custom design

• Does not filter out gaseous pollution such as VOCs

Not commonly used in residen­tial filtration.

A carbon post­filter will help eliminate odor generated by the HEPA filter. An inexpen­sive, frequently changed prefil­ter will extend the life of the HEPA filter.

Filter type


How it works











Mechanism is mounted to ductwork, which statically charges dust. Dust is collected at oppositely charged plates in a filter.

Removes 90% of particulate mat­ter when clean

* No resistance to airflow

* Efficient when clean

* Does not re­quire replace­ment

• Must be adapted for residential use

• Ozone is produced as byproduct of high voltage

• Relatively expensive

• Does not filter out gaseous pollution

• Efficient only when clean

• Generates EMFs

Plates must be cleaned frequently.

Electrostat­ic air filter (passive)

Particulate filter

Electrostatic charge is gener­ated by friction as air moves through special media.

Removes 10 to 15% of particulate matter

• Good for large mold spores and pollen

• No customiza­tion required on some filters used with HVAC

• Inexpensive (washable/ reusable)

• Not efficient for capturing small particles

• Limited ef­ficiency

• Does not filter out gaseous pollution

• Requires fre­quent cleaning to maintain filter efficiency

May be sub­stituted for standard furnace filters.

An inexpensive way to relieve pollen and mold allergies. Medium effi­ciency extended surface (pleated panel) filters are making these obsolete.

TFP (turbu­lent flow precipita­tor)



Turbulent airstream "drops" particles into collection space, where there is no airflow.

Manufacturer claims 100% removal of par­ticulate matter

• No resistance to airflow

• Can be used with ventilator

•Very low main­tenance.

• Does not filter gaseous pol­lution

Actual perfor­mance varies widely.

Filter type


How it works





Partial by­pass filter

Absorption of gaseous pollut­ants

Granules of ab­sorptive material are held in place and separated by a metallic grid. Some air passes through the medium and some flows past unrestricted.

Efficiency varies widely based on amount of air that bypasses the filter

• Allows some air to flow through, thereby cut­ting down air resistance and requiring less powerful fan

• Not suitable where air is highly polluted

• Not suitable in ventilator

Works in con­junction with HVAC, where the same air is repeatedly run through the filter.




Adsorption of gaseous pol­lutants (not for particles)

Gases cling to many-faceted carbon granules.


• Effectively removes gases with high mo­lecular weight

• Offered in standard fur­nace sizes for low-pollution situations

• Does not remove certain lightweight pollutants such as formalde­hyde or carbon monoxide

• Filters become contaminated with use and can release pollutants if not changed

Can be treated to remove more gases.

Must be changed regularly per manufacturer’s recommenda­tions.



Adsorption and transformation of gaseous pol­lutants (not for particles)

Activated alumina is impregnated with potassium permanganate. It acts as a cata­lyst in changing the chemical composition of harmful gases and also acts through adsorp­tion.


• Will remove gases not removed by carbon, includ­ing formalde­hyde

■ Lasts longer than carbon

• Not as adsorp­tive as carbon

• More expen­sive than carbon

Activated alu­mina changes color when depleted.

Air Filtration


Until the 1960s, ventilation in homes occurred naturally, obviating the need for intentional ventilation systems. Homes were loosely built, allowing enough outside air to make its way through the home to keep it fresh. By some ac­counts, this loose construction contributed to as many as three to four air exchanges per hour. Although there were ample air exchanges, there was also an unacceptable amount of en­ergy required to run such a home, and uncon­trolled ventilation through air leakage can cause serious harm to a building. Currently, with energy-efficient construction, much of the unintentional air exchange has been elim­inated. However, while homes were built of more natural, nonpolluting materials in the past, in recent years indoor air has become at least five to ten times more polluted than out­door air and it is often too polluted for opti­mal health. Although minimum air-exchange rates are enforced for commercial structures, this is generally not the case for residential construction, except where exhaust fans are mandated.

Like many other components essential to health, ventilation is considered an “extra” in standard construction. The American Soci­ety for Heating, Refrigeration, and Air Con­ditioning Engineers (ASHRAE) has set a stan­dard of.35 air exchanges per hour, or 15 cubic feet per minute per resident, for residential ventilation. Although this may be sufficient to dispel pollutants created by human activ­ity, it may not be enough to dispel the chem­ical pollution generated by standard con­struction or the thousands of other chemicals introduced into homes through furnishings, clothing, cleaning products, cosmetics, and other scented products. ASHRAE determines its requirements based on the level at which 80 percent of a test population feels comfort­able. It should be noted that it is quite possible to feel comfortable in environments that are polluted enough to be detrimental to health. The human body has the ability to become ac­customed to harmful chemicals, much as one might adapt over time to the toxic effects of tobacco smoke. Whether or not the ASHRAE standard is sufficient to meet health require­ments is irrelevant because in fact most homes are not equipped with ventilation other than spot exhaust fans and do not meet the ASHRAE recommendations.

With tight construction, ventilation strate­gies are necessary in a healthy home to ensure fresh air and dispel odors from everyday liv­ing. Care should be taken to locate the fresh – air supply away from exhaust-air piping and in the best location for receiving an unpol­luted airstream.

Combined Heating and Cooling Systems

Heat pumps are far more energy efficient than electric resistance heat and can be used for both heating and cooling. Heat pumps extract heat from outside air or, in some cases, from a water source. Air-source heat pumps are most common in areas where winter tempera­tures seldom fall below 30 degrees Fahrenheit and where summer cooling loads are high. As temperatures fall below 30 degrees, the heat pump must rely on electric resistance heat­ing to make up the difference, at which point the system loses its economic advantage. Tire main advantages of a heat pump are that heat­ing and cooling needs are met by a single unit, humidity is not added to the air, and opera­tion is quiet.

Cooling Systems

Common types of air conditioners include condensing or refrigerated air conditioners, electric heat pumps as discussed above, and evaporative coolers.

Condensing air conditioners are available either as small units designed to cool one area of a home or as central air conditioners, which will cool an entire home via ductwork. Ad­vantages of central air conditioners are their out-of-the-way location, quiet operation, in­tegration with the forced-air heating system, and greater cooling capacity and efficiency than portable models. However, these central systems consume a lot of energy and cost up to seven times more to operate than evaporative cooling systems. It is important to choose an air conditioning unit that continues to blow air across the cooling coils for a time after the cooler is turned off. This allows any moisture remaining on the coils to be dried off, discour­aging mold growth. Room air conditioners are less expensive to install than central air condi­tioners. Since they cool only designated areas, they save money and energy, but they do tend to be noisy.

Evaporative coolers are practical in very dry areas and are available either as a direct model, which adds humidity to the home, or an indirect model, which does not add humid­ity. The operating costs for evaporative coolers are significantly lower than those for condens­ing units, and evaporative units are fairly in­expensive to install. They bring fresh outdoor air into the living space and exhaust stale air. Evaporative coolers have a lower cooling ca­pacity and work well only in low-humidity conditions, such as those found in the south­western states. Another name for evaporative coolers is swamp coolers. They must be kept clean or they truly become swamps, filled with microorganisms.

When using mechanical air condition­ing, you can save energy and money by keep­ing the windows closed. One exception to this rule is the case of evaporative coolers, which are more efficient when windows are left par­tially open. Air conditioners should be shut off and windows opened at night if it is cool outside. Do not cool unoccupied rooms or homes. Insulating all exterior ducting can save you at least 10 percent of the energy costs of

Type of system

How it works




Heating Systems

Forced air heat

A fan pulls air through a heating unit and distrib­utes the air throughout the house via ducts.

• Can be easily adapted for filtration, humidifi­cation, and dehumidi­fication

• Almost immediate response time

• Inexpensive to operate

• Less comfortable than radiant heat

• Stirs up and fries dust

• Can exacerbate allergies

• Ductwork is architec­turally cumbersome

• Leaky ducts can depressurize home

• Noisy

• Needs regular cleaning

• Metal ductwork grounds negative ions

• Fumes from gas or oil fuel can enter airstream

– Insulation particles can enter airstream

• Many of the disadvan­tages of forced air can be rectified by adding filtration to the system at the furnace and where the air enters the room

Radiant hydronic floor heat

Hot water is run through tubing in or under the floor. Natural convection gently distributes heat.

• Even, comfortable heating

• Comfortable at lower temperatures

• Efficient

• Not hot enough to fry dust

• Silent

• Low maintenance

• Easyzonation

• Invisible

• Slow response time

• Initial installation costly

• Does not filter air

• Not practical for cool­ing

• Avoid metal tubing, which can transmit EMFs

Liquid-filled base­board heaters

Hot liquid is circulated through fin tube base­board units and radiates into the room.

• Heats quickly

• Comfortable radiant heat

• Not hot enough to fry dust

• Less expensive than in-floor heating

• Baseboard units are dust traps

• Limits furniture place­ment

• Can be hot to touch

• Heated surfaces of baseboard units may outgas

• Leaks (other than water) may be toxic

Electric radiant floor, wall, or ceil­ing heat

Electric current passes through resistant wiring embedded in walls, floors, or ceilings.

• Even heating

• Comfortable radiant heat

• Expensive to run

• Can create high levels of EMFs

• Less expensive systems run hotter and fry dust

• Not recommended in a healthy home because of EMFs and high degree of energy consumption

Type of system

How it works




Electric base­board heating

Individual units are plugged in.

• Initial installation inex­pensive and easy

• Does not require cen­tralized machinery

• Puts heat only where required

• Expensive to run

• Hot to touch

■ Traps and fries dust

• Emits EMFs

* Heated surfaces may offgas



Wood fire is contained in a noncombustible stove. Heat radiates into the room.

• Radiant heat source

• No central equipment required

• Inexpensive to install and operate

• Messy to run and requires high mainte­nance

• Burn and fire hazard

• Chimney can be sub­ject to backdrafting

• Burning wood pro­duces more than 200 toxic byproducts of combustion and stud­ies show higher rate of respiratory problems in children where woodstoves are the primary heat source

• Most heat escapes up the chimney

• Not recommended in a healthy home

* Choose the most effi­cient models available, burn hardwoods, and clean the flue often

Masonry heater (Kachelofen)

Heat from wood fire travels through a series of masonry chambers, is stored in the masonry mass, and slowly radi­ates into the room.

. Very efficient use of fuel

• Requires less tending than conventional woodstoves

• Burns cleaner

• Produces comfortable radiant heat that does not fry dust or burn people

• Inexpensive to oper­ate, requires no further equipment

• Can incorporate cook – stove or oven

• Can be an architectural feature

• Short duration of fire time; full combustion of gases creates little pollution inside and outside the home

• Initial installation is costly

• Generates a small amount of combustion byproducts

• Less convenient than central heating systems

• Considered by Bau – Biologie as one of the most healthful ways to heat

Type of system

How it works




Passive solar heating

Heat from the sun is captured through glaz­ing and stored in build­ing components with high thermal mass such as concrete and adobe walls and floors.

• No operation expenses

• Does not consume fossil fuels

• Does not fry or circu­late dust

• Dependent on weather

• Requires a relatively high degree of human interaction.

• Must be incorporated into architecture

• For more information, refer to the Further Reading section

Heat pump

Heat or cold is extracted from outside air and transferred to inside air.

• Can be used for heat­ing or cooling

• Cost effective in mild climate

• Quiet

• Not cost effective where temperatures are frequently below 30 degrees F.

* Uses Freon (an atmospheric ozone depleted as transfer medium

Cooling Systems

Central refriger­ant coolers

Freon gas is passed through a condenser. Heat is transferred to the outdoors and the cool air is distributed throughout the house via ductwork.

• Can also dehumidify air

• Will handle large cool­ing load

• Can be quiet to operate if condenser is remote

• Shares ductwork with central heating

* Expensive to operate

* High energy consump­tion

• Uses Freon (an atmospheric ozone depleted

• Requires maintenance to prevent mold

• Drip pan must be inspected and cleaned regularly for mold-free operation

Room refrigerant coolers

Freon gas is passed through a condenser. Heat is transferred to the outdoors and the cooled air is blown into the room.

• Inexpensive initial installation

• Because it cools only designated areas, energy waste and expense are reduced

• High energy consump­tion

• Uses Freon

– Requires maintenance to prevent mold

• Noisy

Evaporative (swamp) coolers

Air is passed over a wet medium. As evapora­tion occurs, air is cooled and then blown into the home.

• Low cost initially and when in operation

• Uses no CFCs or HCFCs

• Requires 80% less energy than refrigerant coolers

• Works well in hot, dry climates

• Subject to mold and other microorganism growth

• Not suitable in humid conditions

• Cannot take as large a load as refrigerant models

• Can be noisy

• Requires maintenance to keep mold-free and needs frost protection in cold winter climates

• Should be drained and cleaned monthly

cooling. Maintain systems regularly, keeping coils and filters clean. Locate the cooler in a shaded area.

The Ideal Heating for Room Climate and Health

Because humans do not have the ability to with­stand the natural elements, we wear clothes and build shelters. In cold climates we heat those shel­ters. Many systems have been invented for heating the home, but not all systems are created equal. After examining the criteria that create health and a comfortable indoor climate, I chose to focus my career on the creation of Kachelofens, or masonry oven heating systems, because of their superior quality and performance. A Kachelofen-Masonry Heater is an individually designed, technically cal­culated, thermal mass wood-fired heating system.

From a Building Biology point of view, let us ex­amine the criteria for creating a comfortable and healthy indoor environment and discover why the Masonry Heater is one of the best heating systems for meeting these criteria.

1. Type of Heat: A heating system should create radiant heat, like the heat from the sun. With a radiant heat source, the room air tempera­ture can stay relatively low at 18 to 20 degrees Celsius (64 to 68 degrees Fahrenheit) and still be comfortably warm because, unlike the con­vection heat from a forced-air source, radiant

heat warms walls, floors, and ceilings as well as furniture and bodies and not the room air. Therefore the room air is barely moving, or moving only at low speed, which means no electrostatic charge, no dust circulation, and no transfer of odors. Kachelofens-Masonry Heaters release about 60 to 70 percent radiant heat and only about 30 to 40 percent convec­tion heat, an output not attainable with any other heating system.

2. Temperature: The quality of a heating system should not be measured by high room-air temperatures but rather by low differences be­tween the room-air temperature and the tem­peratures of the walls, ceilings, and floors, as shown in the sketches.

The Ideal Heating for Room Climate and Health

Kachelofen-Masonry Heater

Подпись: Electric Baseboard
Подпись: Iron Wood stove
Подпись: feels most vital when it has the same ion balance as is found in nature. Ideally this would be approximately five positive ions to four negative ions, but homes heated by forced- air or hot appliances create a predominance of positive ions. Dust circulation and electric
Подпись: 3. Heater surface temperature: A heater that has a high surface temperature, such as a radiator or woodstove, causes dust circulation, combustion of dust, and electric discharge of the room air. Electric discharge leads to "dead" air, or a predominance of positive ions. Air

vacuums should have true HEPA filtra­tion or be exhausted to the outside. No chemicals shall be used in the process.

• Prior to occupancy, the air distribution system shall be tested for leakage by a qualified third party or in the presence of the owner or architect. Any leakage greater than 3 percent shall be remedied by the contractor at no additional expense to the owner.

Once the ducts are in place, a regular main­tenance program is essential to maintaining a healthy system. Identify a professional main­tenance company that uses high-powered duct cleaning equipment. Avoid the use of chemical cleaners.

Masonry Ovens

From a Building Biology perspective, the ideal heating system would have the following fea­tures:

• It would be a radiant source.

• It would not rob the air of negative ions. (When air is forced through metal duct­work, negative ions will be attracted to the ductwork and room air ions will be de­pleted.)

• The appliance would not be hot enough to fry dust.

• It would not create “temperature monot­ony” (having all rooms the same temper­ature, which Building Biology considers unhealthy) or drafts.

discharge are major irritants to mucous mem­branes and cause many chronic illnesses and allergies. Since the surface temperatures of Kachelofens-Masonry Heaters are below no degrees Celsius, dust circulation, combustion of dust, and electric discharge of the room air do not occur.

4. Humidity: Room air should have a relative humidity of approximately 50 to 60 percent, which can be achieved only by radiant heat. Heating systems operating with mainly con­vection heat will bring the relative humidity in a room down to 30 percent. To compensate, some forced-air systems have built-in humid­ifiers, but these can cause condensation and mold buildup in the ductwork.

5. Temperature gradients: Convection heat cre­ates horizontal layers of air in a room, with temperature differences up to 10 degrees Cel­sius from floor to ceiling, resulting in hot heads and cold feet. The temperature differences in rooms with radiant heat from Kachelofens – Masonry Heaters are only 1 to 2 degrees Cel­sius, meaning the room is evenly heated.

6. Electromagnetic fields: Heating systems with mainly convection heat (electric and hot – water baseboard heaters and hot-water radia­tors) create electromagnetic fields that cause electric stress. Permanent electric stress can be the cause of illnesses. Kachelofens-Masonry Heaters do not cause electromagnetic fields or electric stress.

7. Ionization of room air: Wood fire creates a neg­ative ionization of the room air. Why is this important? An ion has either a positive or a negative charge. We have positive and nega­tive ions in our body, but when we run, walk, work, or just generally move we lose negative ions. We are left with positive ions, or a posi­tive charge in our body, and we need to find a source of negative ions to balance our positive charge. Wood fire is one of the best sources to recharge our body with negative ions.

8. Noise:The only noise created by Kachelofens – Masonry Heaters is the cozy crackling of the wood fire.

9. Environmental impact: Of all heating systems, the Kachelofen-Masonry Heater has the low­est overall impact on our environment, from production of the building materials to instal­lation, to the amount of fuel required and pol­lution generated, to disposal after a lifetime of at least 80 years. Unlike a woodstove, which in cold climates must burn wood constantly to heat a home, a masonry oven is fired only for a short duration, fully burning the combus­tion gases and storing heat in its mass walls. It therefore uses far less wood than a woodstove and creates very little pollution in the form of smoke.

A study of Kachelofens-Masonry Heaters con­ducted by the Technical University of Vienna showed the following:

• There would be minimal byproducts of combustion.

Wood heat distributed through a masonry oven can fulfill these criteria. The masonry oven, not to be confused with other types of “fireplaces” or woodburning stoves, is de­signed to burn wood so that the gases are completely combusted. The generated heat circulates through multiple chambers within the oven and is distributed into the ovens mas­sive walls before the relatively clean and cool




Room Temperature

18 to 20° C

18 to 20° C

Temperature gradient

1 to 2° C

2 to 4° C

Wall temperature

20 to 22° C

18 to 20° C


40 to 60 %

40 to 60 %

Air movement

<0.1 m/s

<0.1 m/s

Dust circulation





low and pleasant










The Baubiologische Institut Rosenheim (Ger­many) graded the various heating systems based on the criteria discussed above and came up with the following results:

Forced air/fuel oil 7 points

Hot water in floor/fuel oil 19 points

Wood-fired iron stove 21 points

Kachelofen-Masonry Heater 66 points

The masonry oven and its health, comfort, and ecological benefits are little known in North Amer­ica, where forced-air heating is the norm. If you are interested in heating your home in this time – tested manner you will need to seek out a mason trained in the art of masonry oven building and in­stallation. To find a certified mason in your vicin­ity you can refer to the member directory of The Masonry Heater Association of North America at mha-net. org.

Ernst Kiesling, an Austrian-educated structural engineer, has had a lifelong attraction to healthy living and green building methods. He has been involved with Kachelofens-Masonry Heaters for 31 years, starting out as a teacherfor the profession at a vocational school in Austria and then going into business building individually designed Kache­lofens-Masonry Heaters. After immigrating to Nova Scotia, Canada, he started Kiesling Construc­tion Ltd. to bring the goodness of the Kachelofen – Masonry Heaterto Canada. He can be contacted at Canadian Kachelofen, ermared@ns. sympatico. ca.

exhaust goes up the chimney. Most countries in northern Europe have developed this type of heating to perfection and masonry ovens are common there. There are many masons in the US trained in the art of masonry oven building. The Masonry Heater Association of North America has an informative website that lists trained and certified heater masons by location.